New MS3 Owner: Turbo Q's.

[mrbeal]

Originally Posted by SRTie4k There are several things at play here. 1. You will get used to the feeling of the torque after a while, and thus it will seem like it is less "violent" than before. 2. The car reacts to different ambient temps very dramatically. Stomping the throttle at 60*F will give you that violent throw back in your seat, whereas stomping it at 90*F will not. Why? Because the density of air that the turbo shoves into the engine is much greater at 60* than it is at 90*. The more air that the cylinders take in, the more power it will put out (so long as you aren't being limited by fuel/knock). 3. Knock can creep up in some instances and cut your timing down quite a bit. This will feel like hesitation. It's caused by very hot intake temps or piss gas, i.e. less than 93. 4. That "wall" that you are talking about is right around 5500-5600. That is the point at which the turbo steps out of its efficiency range and starts blowing lots of hot air. Because of this fact, Mazda tuned the throttle plate to close at this RPM range to redline. Less, hotter air = less power, or the "wall". Shifting at 5600 will alleviate this. Tuning will also help remedy this, although it will never go away completely with the tiny K04 (the turbo).

And there you have it... OP, just wait till winter and get good gas. Poor fuel and nothing but HOT air will kill performance.

Another thing I thought of is... does this car "learn" how you drive and adjust accordingly? If so, after the break in period disconnect the battery and hit the break pedal to "reset" the system. THEN go out and drive it like its supposed to be driven. If you drive it like a grandma during the breaking period and the computer learns that that's how you drive you have to tell the computer otherwise. Good luck, I hope to get a Speed3 soon myself.

[Magsz]

SRT,

Great post, thank you very much for the technical information and the education, it is appreciated.

I definitely do drive like a grandma so hopefully the car isnt paying too close attention to me.

To the other guy...what IS the measurement for the boost? Is it literally, 8 PSI? I keep forgetting some people such as yourself are born knowing everything and pleebs like us need to learn.

[whyte07]

yes yes i want 8k psi...maybe i could fly my ms3 to the moon

[Magsz]

Originally Posted by whyte07 yes yes i want 8k psi...maybe i could fly my ms3 to the moon

What parts will get me to 8k psi so i can go to the moon? They're simple bolt ons right? Or can i simply duct tape them to the car?

In all seriousness, pressure washers output between 2k and 5k psi and that is a fairly small machine. I figured a car lugging around 3 thousand plus pounds might operate at those ranges. Forgive me for not knowing everything. I bow before thee as i am now learned!

[jeopardy98]

Why don't you donate to the board and I bet you would be taken more seriously and receive a good bit more help. And yes boost is literally measured in PSI. It is forced air induction meaning air is forced into the turbo.

[CW42]

srt: Some great info in your post. Thanks. Could explain my dip in performance as well. Would the extreme heat we've been experiencing in my area also cause a rough idle and broken exhaust note? It seems to steady out when it cools off a bit but seems to really hate running in the heat.

[CodeMan]

Mine idles a little lopey too, almost like it has mild cams or something. I wouldn't know the difference though. I bought the car this week and it's been ~110 degrees every day since. One throttle tip in and it's heatsoaked.

[texasboy21]

Does anyone experience a loss of boost above 5500rpms?

[IPuOnU]

Originally Posted by texasboy21 Does anyone experience a loss of boost above 5500rpms?

Reading> you......

[texasboy21]

Originally Posted by IPuOnU Reading> you......

Its was a joke..I know all to well about smaller Borg Warner turbo's boost characteristics.

That said, my K04 will hold 15.5psi all the way to redline, well 5800RPMs at least.

[jlsspeed4]

To the OP, I think I'll be the only one can fix your problem! Here is what you need to do, but it might cost you a little. Put your MS3 aside and don't drive it for couple days, then go rent a Prius and drive it for couple days. Return the Prius, then drive your MS3, I'll guarantee you gonna get your "whoa" feeling back!

[ztnedman1]

-You guys need to monitor. I would put large sums of money that you guys are knocking + heat soaked. Not all gas stations and not all 93 is created equal, not even a little.

-the pop pop pop at idle is normal

-If you guys have done no cooling mods then you will be heat soaked for 10+mins if you drive you car park it then drive again in this weather and thats assuming you keep moving. If you are stopping and going you will remain heat soaked.

-One tip in does not heatsoak make. Tip in will actually lower the BAT's. More airflow = cooler BAT's but boost adds heat. Monitor... you will see this.

[ztnedman1]

Originally Posted by mrbeal And there you have it... OP, just wait till winter and get good gas. Poor fuel and nothing but HOT air will kill performance. Another thing I thought of is... does this car "learn" how you drive and adjust accordingly? If so, after the break in period disconnect the battery and hit the break pedal to "reset" the system. THEN go out and drive it like its supposed to be driven. If you drive it like a grandma during the breaking period and the computer learns that that's how you drive you have to tell the computer otherwise. Good luck, I hope to get a Speed3 soon myself.

The main goal of a break in is to seat the piston rings properly. The ECU has NOTHING to do with it.

[CW42]

This car seems strange to me if it only operates properly under completely ideal temperatures. The reason cars are computerized is to prevent this. Really pathetic engineering if this is true. I've never had a car run like crap on either side of a certain temperature.

[ztnedman1]

Originally Posted by CW42 This car seems strange to me if it only operates properly under completely ideal temperatures. The reason cars are computerized is to prevent this. Really pathetic engineering if this is true. I've never had a car run like crap on either side of a certain temperature.

This must be your first turbo car?

All turbo cars have issues in Hot humid weather. Turbos generate heat, heat = detonation. The intercooler is a heat exchanger to remove the heat created from pressurization but when it is 100 and humid the efficency of any heat exchanger goes to shit. Just like an AC unit having issues on a very hot humid day. A top mount is not helped by sitting on top of an engine, however boost lag is less with a top mount and that is the comprise Mazda and Subaru make.

Get an AP, monitor, tune, run ethanol, problem solved.

[texasboy21]

Originally Posted by CW42 This car seems strange to me if it only operates properly under completely ideal temperatures. The reason cars are computerized is to prevent this. Really pathetic engineering if this is true. I've never had a car run like crap on either side of a certain temperature.

This must be your first trubo'd car based on your statement about ideal temperatures.

As for the ECU being able to prevent that from happening, I somewhat agree. Audi ME7.X ECUs that I am more familiar with are much more responsive, and adaptive. Those cars can adjust + or - 25% of the standard reading.

For example, you can run a fuel injector 20% larger than stock, and the ECU will respond by pulling -20% of the fueling to compensate (to maintain the proper a/f ratio). Audis are not open source however, therefore we have cookie cutter tunes; so that 25% of adjustment is what "dials in" the tune to the mods on the car, instead of internet/dyno/DIY tuners using an access port.

[CW42]

Shouldn't matter if they built it with a turbo or two jet engines on the sides of the car. The computer should be designed to adapt and compensate unless there's a malfunction. I've NEVER heard of any other car having a problem with temperature. This is what leads me to think there's a bigger issue with my car with the heat issue. Mine runs bad in any climate when the engine is warm but a LOT worse in the summer heat. I don't understand why a car can't function properly just because the engine is at proper operating temps.

[ms3rick]

U need to read @Lex 's blog about turbo chargers and hot air.


Sent from my dizzLe using RaWr powers!

[pawlwawl06]

Originally Posted by SRTie4k 2. The car reacts to different ambient temps very dramatically. Stomping the throttle at 60*F will give you that violent throw back in your seat, whereas stomping it at 90*F will not. Why? Because the density of air that the turbo shoves into the engine is much greater at 60* than it is at 90*. The more air that the cylinders take in, the more power it will put out (so long as you aren't being limited by fuel/knock). .

I think this has been my problem. I bought my car at the end of May, when the temperatures were still in the 70s and humidity was low. I thoroughly enjoyed the car for the first few weeks, but every since then, we have had 80-90 degree weather every day, and very humid air. The car has felt sluggish all summer. One morning, I left work when it was very cool out, and I could immediately feel the difference in the car's power. It put a smile back on my face.

[CW42]

The air density issue totally makes sense to me and it gives me some peace of mind because I was getting a bit paranoid about the poor performance. The thing that's bad about that is that people in warmer climates are obviously getting completely ripped off buying this car instead of a regular Mazda 3. There's such a small window to really enjoy this car. No power in the summer and in the winter when it's full of power, the winter rims and tires are on and it's too dangerous to enjoy driving most of the time. Stupid really. Why wouldn't these cars come with some sort of induction cooling built in. Seems like an oversight on Mazda's part and a lot of false advertising where this car is concerned.

[painfulpillow]

Thats how it is with every car, get a bigger intercooler if you dont want it to notice it as much

[pawlwawl06]

Now, would hot, humid air cause a noticeable change in PSI on a boost gauge? I have noticed boost only topping off around 13 PSI in 3rd and 4th gear over the past few weeks. I'm not referring to the dash gauge, that dumb thing always registers 15 PSI at full throttle and 3k+ RPMs. I have an aftermarket gauge.

[jeopardy98]

Hot humid air causes air molecules to spread out becoming less dense which in turn will not allow as much air to be forced through the turbo hence lower boost. Basic science here folks.